I came to US less than a decade ago and English is not my first language. Even though I learned how to read and write English in school, I did not speak English reasonably well until I got married to someone who did not speak my language. Well, English was not her first language as well but we found it was easier to use English to communicate than trying to learn each others language. I think the same holds for programming too. If everyone expressed their ideas in their own language, the knowledge would become too scattered. Should English be mandatory? Probably not. Most people wouldn't need it. My family was mostly farmers and most of them would never need to know English to lead a useful life. I wouldn't say successful life because it has different meanings in different parts of the world.

I don't wish to enter a holy war but English in programming may have nothing to do with 'Ugly American' programmer. It may just be a convenient way to collaborate for people speaking different languages. It could have been any language. May be in the future we will code and comment in Chinese. If that happens it probably wouldn't be because of 'Ugly Chinese' programmers, rather it would be because more people in more countries use Chinese to communicate with outsiders.